Oprah Winfrey provides a very unique service to the public. She is, in essence, irreplaceable, therefore a small shift in demand for her show or magazine will have a large impact on her salary. There is no way you can produce another Oprah so her supply curve is perfectly inelastic. The same is for professional athletes. The best soccer player in the world’s supply curve is perfectly inelastic.
Suvan's IB Economics Blog 